Phenolphthalein diisovalerate.



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HERD/[ANN VIETH, 0F LUDWIGSHAFEN-ON-ZPHE-RHINE, GERMANY, ASSIGNOR TO THEFIRM OF KNOLL AND COMPANY, OF LUDWIGSHAFEN-ON-THE-RHINE, GERMANY.

PHENOLPHTHALEIN DIISOVALERATE.

No Drawing.

Patented July 25, 1911.

(Specimens) To all whom it may concern:

Be it known that I, HERMANN VIETH, a subject of the German Emperor,residing at Ludwigshafen-on-the-Rhine, Germany, have invented a certainnew and useful Phenolphthalein Di-isovalerate, of which the following isspecification.

Phenolphthalein, which has for some years been in use as an aperient,has the defect, that it is liable to produce internal pains, if taken bysensitive persons. It has been found, that this defect may be completelyavoided by administering instead of phenolphthalein its divaleryl-acidester. This ester has a much milder action, because by its use theanesthetic and antispastic action of valeric acid or its ester is at thesame time brought into play. The efiective dose is about 0.4'grams. Theproduct is administered internally, for instance in the shape oftabloids.

Phenolphthalein di-isovalerate may be obtained: by treatingphenolphthalein with the halids, anhydrids or esters of isovaleric acid;or by causing isovaleric acid to act on phenolphthalein in the presenceof'a condensing agent.

Example: 5 parts of phenolphthalein are heated with 6 parts ofisovaleryl bromid on a water-bath, until the generation of hydrobromicacid is finished. The mass resulting from the reaction is dissolved inbenzene and the solution shaken with a dilute solution of caustic soda.Instead of adding the benzene to the said mass it may be added to theraw materials as a diluent before the reaction. The benzene solutionthus obtained is then separated from the residue, and the benzene 1Sevaporated, leaving behind the desired ester, which may be thenrecrystallized from alcohol. The yield thus obtained is almost equal tothe theoretical quantity. The process may be illustrated by thefollowing equation: o 1 1' 0 +20 H,Q.Br=

20 714 4 5 2o 12Q4'( 5 B )2 If instead of the bromid the correspondingquantity of chlorid is employed, it is advantageous to heat up to about130 0., because the reaction takes place less easily than with thebromid. If a substance capable of-separating the halogen-hydrogencompound, such as pyridin in approximately equivalent quantity, is addedto the mixture subjected to the reaction, the latter takes place atordinary temperature. The process may be modified also by shaking thealkaline solution of phenolphthalein with isovaleryl halid, according toSchotten- Baumann' s reaction, during which rocess the materialsubjected tothe reaction 1s preferably cooled. The same ester may beobtained also by heating instead of the isovaleryl halid the anhydrid oran ester of iso- Valeric acid with phenolphthalein, preferably to 200 C.with a small quantity of a substance capable of splitting up esters,such as caustic soda. Finally the desired ester of isovaleric acid maybe obtained by treating a mixture of 2 molecules of isovaleric acid withone molecule of phenolphthalein with phosgen in the presence of pyridin.

Phenolphthalein di-isovalerate has the sha e of a white crystallinepowder, which unlike free phenolphthalein is easily soluble in benzeneand chloroform. It is insoluble in a caustic soda solution, but whenheated with the same it is gradually decomposed While imparting to theliquid a red color. Its melting point is about 110 C.

What I claim is 1. The process for the production of phenolphthaleindi-isovalerate, which consists in treating phenolphthalein with aderivative of isovaleric acid, which contains the isova-leryl radical,washing the product of the reaction with a dilute solution of causticsoda and re-crystallizing.

2. The process for the production of phenolphthalein di-isovalerate,which consists in treating phenolphthalein with a halid of isovalericacid, washing the product of the reaction with a dilute solution ofcaustic soda and re-crystallizing, substantially as described.

3. As a new product, phenolphthalein diisovalerate, being a whitecrystalline'powder melting at about 110 C.,'easily soluble In testimonywhereof I- have hereunto set in benzene and chloroform, insoluble in jmy hand in presence of two subscribing witcaustic soda solution, butundergoing grad j nesses.

ual decomposition when heated Withthe HERMANN VIETH. same whileimparting to the liquid 3. red \Vitnesses:

tintQand applicable as a mild aper'ient, sub- ALBERT KNOLL,

stzuitidlly as described. HERMANN TAEGER.

